Pulse wave sensor

Abstract

Pulse wave sensor includes strain generating body with circular opening, resin layer covering strain generating body's one surface, and strain gauge provided on strain generating body's other surface opposite to one surface and including Cr mixed phase film as resistor. Where circular opening diameter is d [mm] and strain generating body thickness is t [mm], when material of strain generating body is SUS and d is 32, 22, 13, and 7, required range of t is 0.059≤t≤0.124, 0.046≤t≤0.099, 0.030≤t≤0.067, and 0.026≤t≤0.034, respectively, when the material is copper and d is 32, 22, 13, and 7, required range of t is 0.084≤t≤0.166, 0.066≤t≤0.132, 0.044≤t≤0.088, and 0.032≤t≤0.050, respectively, and when the material is aluminum and d is 32, 22, 13, and 7, required range of t is 0.097≤t≤0.212, 0.079≤t<0.168, 0.050<<0.107, 0.038<t<0.063, respectively. Pulse wave sensor detects pulse wave based on change in resistance value of resistor upon deformation of strain generating body.

1 . A pulse wave sensor, comprising:
 a strain generating body with a circular opening;   a resin layer covering one surface of the strain generating body; and   a strain gauge provided on the other surface of the strain generating body positioned on a side opposite to the one surface, the strain gauge including a Cr mixed phase film as a resistor,   wherein where a diameter of the circular opening is d [mm] and a thickness of the strain generating body is t [mm],   when a material of the strain generating body is SUS and d is 32, a required range of t is 0.059≤t≤0.124,   when the material is SUS and d is 22, a required range of t is 0.046≤t≤0.099,   when the material is SUS and d is 13, a required range of t is 0.030≤t≤0.067,   when the material is SUS and d is 7, a required range of t is 0.026≤t≤0.034,   when the material is copper and d is 32, a required range of t is 0.084<t<0.166,   when the material is copper and d is 22, a required range of t is 0.066≤t<0.132,   when the material is copper and d is 13, a required range of tis 0.044≤t≤0.088,   when the material is copper and d is 7, a required range of t is 0.032≤t<0.050,   when the material is aluminum and d is 32, a required range of t is 0.097≤t≤0.212,   when the material is aluminum and d is 22, a required range of tis 0.079≤t≤0.168,   when the material is aluminum and d is 13, a required range of tis 0.050<t<0.107,   when the material is aluminum and d is 7, a required range of tis 0.038<t<0.063, and   the pulse wave sensor is configured to detect a pulse wave based on a change in a resistance value of the resistor in response to a deformation of the strain generating body.   
     
     
         2 . A pulse wave sensor, comprising:
 a strain generating body;   a resin layer covering one surface of the strain generating body; and   a strain gauge provided on the other surface of the strain generating body positioned on a side opposite to the one surface, the strain gauge including a Cr mixed phase film as a resistor,   wherein the strain generating body includes:
 a base portion with a circular opening; 
 a beam portion bridging an inside of the base portion; and 
 a load portion provided on the beam portion, 
   the strain generating body has a flat plate shape, and   the pulse wave sensor is configured to detect a pulse wave based on a change in a resistance value of the resistor in response to a deformation of the strain generating body.   
     
     
         3 . A pulse wave sensor, comprising:
 a strain generating body made of a nonmetallic material; and   a strain gauge provided on the strain generating body and including a Cr mixed phase film as a resistor,   wherein the strain generating body includes:
 a base portion with a circular opening; 
 a beam portion bridging an inside of the base portion; and 
 a load portion provided on the beam portion, 
   the strain generating body has a flat plate shape, and   the pulse wave sensor is configured to detect a pulse wave based on a change in a resistance value of the resistor in response to a deformation of the strain generating body.   
     
     
         4 . The pulse wave sensor according to  claim 3 , further comprising:
 a resin layer covering one surface of the strain generating body,   wherein the strain gauge is provided on the other surface of the strain generating body positioned on a side opposite to the one surface.   
     
     
         5 . The pulse wave sensor according to  claim 1 ,
 wherein the strain generating body includes:
 a base portion with a circular opening; 
 a beam portion bridging an inside of the base portion; and 
 a load portion provided on the beam portion. 
   
     
     
         6 . The pulse wave sensor according to  claim 5 ,
 wherein the strain generating body has a flat plate shape.   
     
     
         7 . The pulse wave sensor according to  claim 6 ,
 wherein the beam portion has two beams that cross each other in a cross shape in a plan view,   a region where the two beams cross includes a center of the circular opening, and   the load portion is provided on the region where the two beams cross.   
     
     
         8 . The pulse wave sensor according to  claim 7 ,
 wherein the pulse wave sensor includes four strain gauges, each of which is the strain gauge,   two of the four strain gauges are positioned on the beam having its longitudinal direction in a first direction, at a portion of the beam close to the load portion, so that the two of the four strain gauges face each other across the load portion in the plan view, and   the other two of the four strain gauges are positioned on the beam having its longitudinal direction in a second direction orthogonal to the first direction, at a portion of the beam close to the base portion, so that the other two of the four strain gauges face each other across the load portion in the plan view.   
     
     
         9 . The pulse wave sensor according to  claim 7 ,
 wherein a length of each of the beams is approximately equal to a diameter of the circular opening.   
     
     
         10 . The pulse wave sensor according to  claim 7 ,
 wherein in each of the beams, a width other than the region where the two beams cross is constant.   
     
     
         11 . The pulse wave sensor according to  claim 1 , further comprising:
 a second resin layer provided on the other surface of the strain generating body and covering the strain gauge.   
     
     
         12 - 28 . (canceled)